I'm a bit desperate for help. I've had this cactus for 5 years already and never had an issue until recently. The base of the cactus is hard to the touch so I'm assuming it's healthy. However the top of the cactus is getting a little squishy and the tips are beginning to rot off. Does anyone have any suggestions as to what's going on. I've already had to cut some of the rot earlier this month. And now new rot is forming again. I've been having this issue for the past 3 weeks.
For care: I fertilized the cactus earlier this month with a cactus fertilizer and I'm acclimating it to the outdoor weather. I wait until the day gets above 60 and then I put the cactus outside until 7 when I bring it back in for the night. I water it maybe once a week or until the soil moisture meter says dry.